1. Field of the Invention
The present invention relates to a plasma display panel, and more particularly, to a barrier rib structure of a plasma display panel.
2. Description of the Background Art
In general, in a plasma display panel, barrier ribs formed between a front panel and a rear panel constitute a unit cell and main discharge gas such as Neon (Ne), Helium (He), or mixed gas (Ne+He) of Neon and Helium and inert gas containing a small amount of Xenon fill each cell. When discharge is performed by a high frequency voltage, the inert gas generates vacuum ultraviolet rays and allows a phosphor formed between the barrier ribs to emit light, and thus an image is embodied. Such a plasma display panel is made to be thin and light, so that it is in the spotlight as a next generation display device.
FIG. 1 is a view illustrating a structure of a general plasma display panel.
As shown in FIG. 1, in the plasma display panel, a front panel 100 in which a plurality of sustain electrode pairs formed in a pair of a scan electrode 102 and a sustain electrode 103 are arranged in a front glass 101, that is, a display surface in which an image is displayed and a rear panel 100 in which a plurality of address electrodes 113 is arranged to intersect the plurality of sustain electrode pairs on a rear glass 111 forming a rear surface are coupled to be disposed apart a predetermined distance from and to be parallel to each other.
The front panel 100 performs reciprocal discharge in one discharge cell and comprises pairs of the scan electrode 102 and the sustain electrode 103 for sustaining light emitting of a cell, i.e., the scan electrode 102 and the sustain electrode 103 provided with a transparent electrode (a) made of a transparent ITO material and a bus electrode (b) made of a metal material. The scan electrode 102 and the sustain electrode 103 prevent a discharge current from flowing and are covered with a dielectric layer 104 for isolating the electrode pair, and a protective layer 105 evaporated with a magnesium oxide (MgO) is formed on an upper surface of the upper dielectric layer 104 to facilitate a discharge condition.
In the rear panel 110, stripe type barrier ribs 112 for forming a plurality of discharge spaces, i.e., discharge cells are disposed in parallel. Further, many address electrodes 113 for generating vacuum ultraviolet rays by performing address discharge are disposed in parallel to the barrier rib 112. A RGB phosphors 114 emitting visible rays for displaying an image upon address discharge are coated in the upper surface of the rear panel 110. A lower dielectric layer 115 for protecting the address electrode 113 is formed between the address electrode 113 and the phosphor 114.
Hereinafter, a barrier rib structure of a plasma display panel having such a structure will be described.
A conventional plasma display panel has several barrier rib structures. A stripe type barrier rib structure and a well type barrier rib structure as representative barrier rib structures among them will be described as follows.
FIGS. 2A and 2B are diagrams illustrating a barrier rib structure of a conventional plasma display panel.
In FIG. 2A, a stripe type barrier rib structure of the plasma display panel is shown. Referring to FIG. 2A, the stripe type barrier rib structure has a structure in which a barrier rib 210 is vertical to a sustain electrode consisting of a bus electrode 220 and a transparent electrode 230 and disposed in a stripe shape.
In FIG. 2B, a well type barrier rib structure of the plasma display panel is shown. Referring to FIG. 2B, the well type barrier rib structure has a structure in which a barrier rib 310 is horizontal or vertical to a sustain electrode consisting of a bus electrode 320 and a transparent electrode 330 and disposed in a well shape.
In addition to the above structures, there are a triangle type barrier rib structure, a delta type barrier rib structure, and a waffle type barrier rib structure.
As an example, the waffle type barrier rib structure will be described.
FIG. 3 is a diagram illustrating deformation of a barrier rib upon firing of a barrier rib of the plasma display panel.
Referring to FIG. 3, it can be seen that the edge of the barrier rib is contracted (A′) due to firing of the barrier rib of the plasma display panel. At this time, a discharge cell (A) positioned at the edge of the barrier rib is deformed due to contraction (A′) of the barrier rib. For example, the edge of the barrier rib is contracted (A′) and thus the discharge cell (A) is also contracted (a′) and deformed. Here, filing means an operation of making a hardening material by heating the mixed materials.
Contraction (a′) of the discharge cell (A) due to contraction (A′) of the barrier rib of the plasma display panel has a bad influence on reliability of the plasma display panel. That is, a defective pixel is generated on an effective surface in which an image of the plasma display panel is displayed and thus erroneous discharge occurs upon driving, so that reliability is deteriorated. An effective surface is an area expressing an image and comprises a dummy cell region as well as a discharge cell region for directly expressing an image.
FIG. 4 is a diagram illustrating an influence in which deformation of a barrier rib of the plasma display panel has on an effective surface of the panel.
Referring to FIG. 4, a black spot (A) is generated in the edge of an effective surface 400 of the plasma display panel adjacent to an ineffective surface 410 thereof. The spot is generated as the discharge cell (A) becomes a defective pixel in which discharge is not generated due to deformation of a discharge cell (A) caused by contraction (a′) of a barrier rib upon firing of the barrier rib of a discharge cell (A) shown in FIG. 3.
Therefore, a discharge cell is deformed due to contraction of a barrier rib upon firing of the barrier rib and a defective pixel is generated due to deformation of the discharge cell, so that reliability of the plasma display panel is deteriorated.